Is my red eyed tree frog sick?

[Chrono1081]

Hi guys,

I have two red eyed tree frogs, but I noticed today the one looks pale and discolored on part of his skin. I can't tell if its just color change or if it could be some kind of infection.

Nothing in their tank has changed, and I treat the water that goes into the tank. I feed them gut loaded crickets too.

The frog acts normal, and doesn't sleep on the ground or anything and still hunts crickets and things.

Heres a pic of him:



And now to further confuse things here he is 10 min later, he's back to full color so I think its just the coloring but I wanted to ask to be sure.